Process simulation and analysis for coal pyrolysis with rotary kiln using solid heat carrier

To achieve a clean and efficient conversion of the cheap and abundant small size coal, a coal pyrolysis process with rotary kiln using solid heat carrier was proposed. In the process, a rotary kiln was adopted as the pyrolysis reactor to get uniform mixing between the solid heat carrier and coal. In order to easily control the dust in the process, the bigger size semicoke was used as the solid heat carrier, and meanwhile a mechanical lifter was used to reduce the broken rate of solid heat carrier. Subsequently, a process model was established using Aspen Plus based on the laboratory test data. The process simulation results show it can reduce the heat carrier circulation and generate less wastewater by increasing drying temperature or heat carrier temperature. Under the conditions of drying temperature of 200 ℃, pyrolysis temperature of 600 ℃and solid heat carrier temperature of 800 ℃, the process simulation results show that the mass flowrate of solid heat carrier is about 3.3 times of dry coal to pyrolyzer, and the tar and pyrolysis gas yields are about 7.2% and 10% dry base, respectively. The energy conversion efficiency of such a process can reach above 85%. ©, 2015, China Coal Society. All right reserved.